Over the last few decades, there have been a number of key developments in the study of neural control of arm movement, including the introduction of the concepts of endpoint direction representation, cosine tuning, population coding, continuous trajectory representation, and the finding that neural activity in movement-related areas of the brain such as the motor cortex can be present in the absence of actual movement in paralyzed patients. In addition, basic research over the last 25 years has shown that arm movement is well represented in populations of neurons recorded from the motor cortex. These developments, combined with advances in engineering and technology, have made it possible to create prosthetic devices that are controlled directly by cortical activity. A cortically controlled prosthetic arm would be able to restore the ability of a tetraplegic, a quadriplegic or an amputee to interact with the physical environment to, for example, perform everyday tasks such as feeding oneself, opening doors, or handing a toy to a child. Previous work has demonstrated that monkeys can use spiking activity from the motor cortex to perform closed-loop control of a cursor in 3-dimensional (3D) virtual reality (VR), and can control a robotic arm with indirect visual feedback through a 3D VR display. Others have developed systems for 1- or 2-dimensional (1D/2D) closed-loop brain-control of a cursor using spiking activity, local field potentials, or electroencephalogram activity. These developments, however, have only involved control of a cursor. Furthermore, in prior experiments where a robotic arm or hand was included in the control loop, the subjects did not use it to interact with physical objects, but instead the interaction was VR based. Because physical interaction cannot be fully simulated, the performance of a prosthetic arm cannot be fully evaluated in virtual experiments.
As will be understood, a successful movement prosthetic would have to provide direct interaction with the physical world. However, due to the physical interaction between the subject, the prosthetic device and objects in the workspace, this type of task presents a higher level of difficulty than previous virtual (cursor-control) experiments. A suitable system for use of cortical signals to control a multi jointed prosthetic device for direct real-time interaction with the physical environment has not been demonstrated in the prior art, and there is thus a need for such a system.